BRPI1015168B1 - "Biodiesel fuel, and diesel fuel manufacturing process" - Google Patents

Description

(54) Title: FUEL BIODIESEL, E, PROCESS OF MANUFACTURING A DIESEL FUEL (51) Int.CI .: C10L 1/02; 1/10 C10L; C11C 3/00; C11C 3/10 (30) Unionist Priority: 24/04/2009 FR 0952698 (73) Owner (s): ARKEMA FRANCE (72) Inventor (s): JEAN-LUC DUBOIS

1/20 “BIODIESEL FUEL, E, MANUFACTURING PROCESS FOR A DIESEL FUEL” [0001] The present invention relates to a diesel biofuel consisting of a mixture of esters of fatty acids of natural origin and containing an ester of ω-unsaturated acids comprising a chain with 11 or 13 carbon atoms or the corresponding saturated acids.

[0002] The replacement of fossil fuels to ensure future energy needs is a major concern. In this context, biodiesel is a substitute for fuels made from petroleum (petrodiesel). Biodiesel means fuels using as raw material natural products from agriculture or livestock, that is, renewable.

[0003] This approach, which began several decades ago, has been the subject of important work that led to the commercialization of biofuels for diesel engines. The basis of these works was the use of vegetable oils obtained from seeds of several plants, such as canola, soy, sunflower, palm ... or animal fats that consist of a mixture of triglycerides of organic fatty acids whose The chain length is usually between 16 and 18 carbon atoms.

[0004] Thus, a range of biodiesels known under the abbreviation EMHV for Vegetable Oil Methyl Ester has been developed in which a major molecule is the oleic acid methyl ester. In a similar way, EEHV (ethyl esters of the same vegetable oils) was developed. These biodiesels are known in English under the names FAME and FAEE for, respectively, "Fatty Acid Methyl Ester" and "Fatty Acid Ethyl Ester". They form what is called first generation biodiesels.

[0005] These esters can be obtained through direct transesterification of vegetable oil obtained from the seeds of these plants and by analogy transesterification of animal fat, in the presence of methanol which leads to a mixture of esters whose formulas depend on the nature of the oils or the fats used as fillers.

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2/20 [0006] These esters can also be obtained in a first stage through the hydrolysis of the triglycerides contained in these oils or fats, then in a second stage through esterification with methanol. Between these two steps, it is possible to separate the acids to obtain a mixture of esters enriched in at least one of these esters.

[0007] IUPAC 2001, “Pure and Applied Chemistry 73, 685-744”, contains the fatty acid compositions of a vast majority of oils or fats, the list established in the present case for food use, but which can in any case be used in the manufacture of biodiesel. With the exception of a few “exotic” examples, such as coconut nut oil, palm kernel oil and babassu oil that contain “short” 12-carbon fatty acids, all others are based essentially on saturated C16 and C18 acids or unsaturated.

[0008] In addition a large study conducted by Gerhard Knothe and his colleagues to analyze the key factors in the choice of fatty esters for the formulation of biodiesels. This study is summarized in the article entitled - “Designer” Biodiesel: Optimizing Fatty Ester Composition to Improve Fuels Properties published in “Energy & Fuels” 2008, 22, 1358-1364. This article deals with the influence of the structure of fatty acids, that is, their chain length, the presence or not of double bonds and the presence of hydroxyl functions in their properties in relation to the diesel fuel specifications as defined in the ASTM D6751 standards and EN 14214, and in particular the cetane number, viscosity, cold flow properties and oxidation stability. The conclusion of this study is that methyl oleate is the main base molecule of the mixture whose performance can be improved by adding other specific esters. [0009] This study is essentially technical. On a practical level, it should also be placed in a political perspective, taking into account an additional parameter that is important, namely that this agricultural product or the culture of that product should not have an impact on the development of the culture intended for human consumption indispensable with the evolution of the population

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3/20 worldwide. It is becoming increasingly important to develop industrial crops that are not in competition with food applications.

[0010] To summarize, the selection of one of these routes naturally depends on the “thermal and energetic” properties of the fuels thus obtained, but also on three important additional criteria, namely the compatibility of these fuels with the engines currently used, compliance with the new CO2 emissions and harmonization (non-competition) with crops dedicated to food.

[0011] Also known are the so-called second generation biodiesels that are obtained through the hydrotreating of vegetable oils conducted through the hydrogenation of long chain hydrocarbons, isomerized or not. Paraffin isomerization significantly reduces the cloud point, that is, the temperature at which the paraffins start to crystallize.

[0012] Finally, it was also proposed, in an article by NM Irving published in XVI European Biomass Conférence, 2-6 June 2008, Valencia, Spain under the title “Clean, High Enthalpy biofuels”, to replace the acid function with nitrilation of fatty acid by the nitrile function. These fatty nitriles obtained either through the nitration of natural fatty acids obtained through the hydrolysis of seed oil triglycerides, acids with chains between C12 and C18 and centered mainly on C16, that is, through direct oil nitrilation, seem to give excellent performances as biodiesel. .

[0013] The problem to be solved is, therefore, to find a diesel fuel based on a renewable source, better satisfying the specifications of the biodiesels (ASTM D6751 and EN 14214 standards) and in particular the criteria of the cetane index, the melting points , viscosity and oxidation stability using a source not leading to the production of food products to avoid any “prohibited” competition. These biodiesels must naturally be fully compatible with the ex-petroleum fuels with which they are, until now, most often used in blends.

[0014] Among these possible sources, oils containing

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4/20 hydroxy acids that are not conducive to human food and especially castor. In fact, castor seed has an oil content of approximately 50%. On the other hand, castor oil, which contains more than 80% by weight of ricinoleic acid and approximately 15% by weight of oleic and linoleic acids, has no food application which has an important interest in the current fuel versus food debate . This oil then seems capable of constituting an excellent source for the production of biodiesels and furthermore this plant has a particularly high yield per hectare or can also grow on very difficult land and in low rainfall conditions, where few food plants can be grown , which more reasonably limits competitions with plants for food applications.

[0015] Unfortunately, as G. Knothe revealed on page 1364 of the article “Energy & Fuels” mentioned above, methyl ricinoleate has properties that a priori exclude its use as a basis in a biodiesel application. In fact, its viscosity at low temperature is very high, its melting point is close to 0 ° C and its cetane number well below specification. To complete it, it can be added that its oxidation stability is less than that of methyl oleate and linoleate.

[0016] The use of castor oil in the biodiesel application is also mentioned in the article “Thermoanalytical characterization of castor oil biodiesel” by Marta M. Conceição et al. published in Renewable and Substainable Energy Reviews - 11 (2007) 964-975 (Elsevier). This essentially analytical article illustrates the viscosity problem and also refers to a very high density that is outside diesel specifications. The cetane aspect is addressed only incidentally on page 969 §2 indicating that transesterification reduces the viscosity of the oil without changing the cetane for which the value is not known. The unsuitability of castor for this application is likely due to the presence of the OH radical in β of the double bond. The same problem occurs with the seeds of plants of the genus Lesquerella, including Lesquerella fendleri, from which an oil containing more than 50% by weight of lesquerolic acid is extracted and in mixture, about 35%

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5/20 by weight of various C18 acids, mostly unsaturated.

[0017] The evident interest in castor oil as a basis for biodiesel has led certain researchers, as revealed by G. Knothe, to work on the genetic modification of castor seed species to produce much more oleic acid and less ricinoleic acid. The work of Pilar Rojas-Barros published in Crop Science, vol. 44, January-February 2004, p. 76-80 and Vol. 45, January-February 2005, pgs. 157-162.

[0018] The invention aims to overcome the disadvantages of producing biodiesel from seeds of plants rich in unsaturated hydroxy acids, such as castor and Lesquerella by extracting the oil contained in the seed, transforming the ricinoleic acid and / or the acid lesquerolic oil contained in the form of methyl or ethyl ester through transesterification (or hydrolysis and esterification) and then cracking the latter into ω-unsaturated C11 and / or C13 esters, which may be necessary to be saturated by consecutive hydrogenation of ω-unsaturated esters .

[0019] The invention relates to a biodiesel fuel comprising a mixture of fatty acid esters, said mixture containing at least 1% of a compound of natural non-fossil origin of the formula ROOC- (CH2) n-CH2-R1 in which R is either CH3 or C2H5, n is 7 or 9 and R1 is either C2H5 or CH = CH2.

[0020] The content of the mixture of this compound depends, in part, on the desired performance depending on the specifications and the biodiesel manufacturing process, which can be based on the use of a single source of oilseeds or a combination of seeds (extracts oleaginous plants such as sunflower, canola, soy, peanut, olive, sesame, safflower, copra, palm ...) or, finally, a further mixture of this mixture with biodiesel fuels of different origins or even ex-petroleum diesel fuels with which it is compatible.

[0021] In general, the weight content of the mixture of biodiesel fuels (fatty acid esters) in this compound is between 1 and 100% and preferably between 20 and 70%, more preferably between 30 and 60%.

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6/20 [0022] The compounds of ω-unsaturated esters containing 11 or 13 carbon atoms have, whether or not they have been subjected to further hydrogenation, physicochemical characteristics corresponding to the specifications of the biodiesels. They can be used “neat” in this application. However, for economic reasons, they can be added to a biodiesel of different origin to give them, depending on the amount added, the performance necessary for use.

[0023] Biodiesel fuel means in the sense of the present invention a fuel meeting the specifications of diesel fuels as defined in the ASTM D6751 and EN 14214 standards, including the cetane number, viscosity, cold flow properties and stability oxidation. Preferably, a biodiesel fuel within the meaning of the present invention meets the specifications defined in the book “Biodiesel Handbook”, by Gerhard Knothe, Jon Van Gerpen and Jürgen Krahl, AOCS press, 2005.

[0024] Furthermore, when its manufacturing process is based on the transformation of castor (or Lesquerella) in the form of seeds or oil, it is indispensable in the economic plan to value other esters present in the oil and likely to be used in a fuel composition biodiesel and thus optimize costs.

[0025] For example, a biodiesel fuel made exclusively from castor oil may have the following composition by weight:

C11: 1 methyl ω-undecylenate from 17 to 92%

C16: 1 to 5% methyl palmitate

C18: 1 to 7% methyl stearate

C18: 1 methyl oleate of 3 to 20%

C18: 2 3 to 20% methyl linoleate

C18: 1 OH 0 to 35% methyl ricinoleate [0026] Preferably, the non-fossil compound of natural origin corresponds to the formula CH ₃ OOC- (CH ₂ ) ₈ -R ₁ where R ₁ is or C ₂ H ₅ or CH = CH ₂ or the formula

CH3OOC- (CH2) 10-R1, where R1 is either C2H5 or CH = CH2.

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7/20 [0027] This compound having 11 or 13 carbon atoms is synthesized from castor seeds (Ricinus communis L. and other species) for the compound with 11 atoms and seeds of Lesquerella (Lesquerella fendleri and other species) for the compound with 13 atoms, seeds from which the corresponding oil is extracted according to a perfectly known process.

[0028] Thus, the invention also relates to a process for the manufacture of a diesel fuel as defined above, a process in which the castor and / or Lesquerella seed oil is used as raw material to which the following treatment is subjected:

1) transesterification of oil triglycerides in the presence of a weak alcohol, preferably methanol or ethanol, after separation of the glycerol formed,

2) separation of the non-hydroxylated fatty esters to form a fraction enriched in hydroxy esters,

3) cracking of the hydroxyester fraction of ricinoleic and / or leskerolic acid enriched to form the acid ester of the formula ROOC- (CH2) n-CH2R1 where R is either CH3 or C2H5, n is 7 or 9 and R1 is CH = CH2, without this cracking having an impact on the residual C18 unsaturated esters (oleic, linoleic and linolenic),

4) separation, for example by distillation, of the formed heptanaldehyde and production of an effluent comprising ω-unsaturated esters C11 and / or C13 and hydroxy esters of unprocessed ricinoleic and / or lesquerolic acids in the cracking of step 3, which after mixing with the non-hydroxylated fatty esters separated previously will form said biodiesel fuel.

[0029] In a process variant, step 1 can also be conducted in two stages: hydrolysis of triglycerides and then esterification of the acids formed. [0030] In another process variant, the cracking rate of step 3 is generally between 50 and 70%, the mixture of esters produced in step 4 will contain ω-unsaturated esters C11 and / or C13 and hydroxy esters of ricinoleic and / or acids or lesquerolic. The latter, separated from ω-unsaturated esters, can be advantageously recycled as a step 3 load to increase the overall rate of

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8/20 cracking.

[0031] In another variant of the process, after the glycerol separation, in step 2, it is not possible to separate the non-hydroxylated fatty esters and therefore form a fraction of crude ester, that is, a mixture corresponding to the set of fatty acids, hydroxy acids and others, present in the treated seeds and in the oil they originate. The cracking in step 3 has no impact on the structure of C18 unsaturated esters (oleic, linoleic and linolenic). After separation in step 4 of the heptanaldehyde of the mixture of esters, which consists of ω-unsaturated esters (C11 / C13), ricinoleic and / or lesquerolic hydroxy esters in step 3 and C16 and 18 esters, it is possible, after separation of ω-unsaturated esters , recycle in the load of step 3, the residual fraction of esters essentially the ricinoleic and / or lesquerolic hydroxy esters to obtain a better conversion of the latter.

[0032] This recycling will be advantageously preceded by an enrichment of the referred fraction of ricinoleic and / or lesquerolic hydroxy esters through the extraction of C18 esters (oleic, linoleic and linolenic ...) to avoid an accumulation of the latter in the cracking reactor. This fraction will also be advantageously subjected, before or after the extraction of the C18 esters, to an esterification, to reduce the free fatty acids eventually formed in the cracking that is carried out in the presence of water vapor.

[0033] In another variant of the implementation of the process, to avoid any presence of the acid form of the molecules forming the mixture, an esterification of the effluent leaving the cracking is carried out before any fractionation of the esters. This will avoid the need to separately treat each part that must be included in the mixture constituting biodiesel fuel.

[0034] In another process variant, a hydrogenation fraction can be applied to the C11 and / or C13 unsaturated ester fraction to form the undecanoic ester ROOC (CH ₂ ) ₉ -CH ₃ and / or tridecanoic ROOC- (CH ₂ ) ₁₁ - CH ₃ and that after separating the oleic and linoleic or linolenic esters in turn and the ricinoleic and / or lesquerolic esters do not

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9/20 converted.

[0035] Note that the lesquerolic acid (14-hydroxy-11-eicosanoic acid) extracted from seeds of species of the genus Lesquerella is in a content between 50 and 80%, according to the species in the oil extract in which they occur also two other hydroxy acids: denssipolic acid (12-hydroxy-9,15 octadecadienoic acid) and auricolic acid (14-hydroxy-11,17-eicosadienic acid) which most likely lead to the same compounds, namely esters C11 and C13 and an aldehyde unsaturated with 7 carbons.

[0036] Thus, in the preferred embodiments of the invention:

- after the separation of the heptanaldehyde, the effluent is subjected to a separation of the ω-unsaturated esters C11 and / or C13 and the fraction of the hydroxy esters of the ricinoleic and / or lesquerolic acids is totally or partially recycled in the cracking after being eventually subjected to a cracking esterification with methanol.

- after glycerol separation, the set of esters coming out of transesterification is subject to cracking whose effluent is subjected to a series of successive separations, first of all from heptanal, from ω-unsaturated esters C11 and / or C13, then finally from fatty esters non-hydroxylated, the residual fraction of hydroxy esters of ricinoleic and / or lesquerolic acid not fully or partially recycled in cracking after being subjected, if necessary, to an esterification with methanol, the biodiesel fuel being the mixture of ω-unsaturated esters C11 and / or C13, non-hydroxylated fatty esters and possibly a hydroxylated part of the unconverted ricinoleic and / or lesquerolic acids.

[0037] The oil is usually obtained from seeds through pressure followed by an extraction eventually with the help of an organic solvent such as hexane or acetone.

[0038] The transesterification of the oil is carried out at a temperature between 20 and 80 ° C in the presence of an excess of weak alcohol, preferably methanol and in a basic medium (soda, potassium, sodium or potassium methylate ...) forming the catalyst.

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10/20 [0039] Glycerol / esters (step 2), hydroxy esters / esters (step 2 or 4), ω-unsaturated esters (C11 and / or C13), esters (C16 / C18 / C20) are usually carried out through distillation but may also be by any means known to those skilled in the art.

[0040] The cracking (or pyrolysis) of the esters is carried out at a temperature generally between 500 and 650 ° C in the presence of water vapor. This step is described in the book “Les Procédés de Pétrochimie” by A. Chauvel et al. published by Editions TECHNIP (1986) in the part dedicated to the synthesis of amino-11-undecanoic acid.

[0041] The implementation of the process in its various variants leads, from the same starting material, to obtain a mixture of esters with, together with the ω-undecylenic and / or ω-tridecylenic acid ester, essentially the esters oleic, linoleic, linolenic, stearic and palmitic acids as well as a fraction of ricinoleic and / or lesquerolic ester not converted. The respective contents in its constituents depend on the process chosen for its execution and the objective aimed at performance within the framework of the biodiesel specifications as shown below in the description.

[0042] Another object of the invention is a variant of the implementation of the process of the invention in which the initial step is carried out using as a load, not the oil resulting from the extraction of seeds, but directly the seeds themselves. [0043] In fact, the preparation from oilseed seeds, fatty acid esters was described above in two stages, that is, a stage of extracting oil from seeds in the presence of solvent and eventually a stage of transesterification of that oil. oil in the presence of alcohol and basic catalyst, leading to an ester phase and a glycerol phase.

[0044] In the process variant, the preliminary step of extracting oil from seeds and the step of transesterification of triglycerides are carried out in a single step. This new first stage consists of a reactive grinding process of castor or Lesquerella oil seeds that allows, starting from specifically conditioned seeds and in the presence of weak alcohol and

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11/20 basic catalyst, carry out in a single step the grinding and transesterification reaction of the triglycerides present in the oil, to lead to the simultaneous obtaining of a pie, glycerol and fatty acid esters, including esters of ricinoleic acid and / or leskerolic.

[0045] An object of the invention is a process of manufacturing a biodiesel fuel consisting of a mixture of fatty acid esters, containing said mixture at least 1% of a compound of natural non-fossil origin of formula ROOC4CH2VCH2-R1 in which R is either CH3 or C2H5, n is 7 or 9 and R1 is either C ₂ H ₅ or CH = CH ₂ , a compound having 11 or 13 linear carbon atoms synthesized from castor seeds (Ricinus communis and others) for the compound with 11 atoms and Lesquerella seeds (Lesquerella fendleri and others) for the compound with 13 atoms, having the following steps:

1) conditioning of the seeds having an acidity rate of less than 2 mg KOH / g without previous stripping,

2) placing the conditioned seeds in contact with a weak anhydrous alcohol and an alkaline catalyst in conditions of sufficient temperature and duration to allow the simultaneous extraction and transesterification of the vegetable oil and leading to a mixture comprising the fatty acid esters present in the seed, glycerol and a pie, then

3) separation of the glycerol and the pie formed,

4) cracking of the resulting ester fraction containing a greater proportion of ricinoleic and / or lesquerolic ester to form the acid ester of the formula ROOC- (CH2) n-CH = CH2, without this cracking having an impact on the unsaturated C18 esters present in the charge (oleic, linoleic and linolenic),

5) production of a mixture of esters through separation (through distillation) of the formed heptanaldehyde.

[0046] This process differs from the previous process only in the initial stages of production of the mixture of fatty esters whose end is marked by the separation of glycerol. The set of implementation variants of the first process are naturally applicable to the second; thus the separation of fatty esters from

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12/20 hydroxy esters to feed cracking with a part enriched in hydroxy esters, either afterwards or during steps 2 and 3, either afterwards or during steps 4 and 5, it will increase the cracking performance of hydroxyesters; in this way it will also be possible to esterify the mixture of esters after separation of the heptanaldehyde and, in addition, to hydrogenate if necessary the ω-unsaturated esters C11 and / or C13.

Thus, the mixture of esters is preferably subjected to a separation of ω-unsaturated esters C11 and / or C13, then the non-hydroxylated fatty esters and that the residual hydroxyester fraction of the non-converted ricinoleic and / or lesquerolic acids it is totally or partially recycled in cracking after being subjected to esterification with methanol; the biodiesel fuel constituted by the mixture of ω-unsaturated esters C11 and / or C13, non-hydroxylated fatty esters and possibly a transfer part of hydroxyesters of the non-converted ricinoleic and / or lesquerolic acids.

[0048] This variant of the process according to the invention allows weak alcohol to react "in situ" with the oil contained in the heart of the seed and on the other hand to react the same alcohol with triglycerides for transesterification, alcohol playing the role of extraction solvent and reagent.

[0049] An advantage of the process variant versus conventional processes lies in the low amounts of water used. Crude oil refining operations, for example, are major consumers of water. This water saving is an important asset in the development of this technology in developing countries and to a lesser extent in rich countries, since water tends to become an essential and increasingly expensive commodity. [0050] The first stage of the process consists of conditioning the castor seeds or Lesquerella seeds, used alone or in mixture with other seeds of oilseeds, oil-proteins or protein crops. This conditioning is done on the whole seeds. It comprises a first pressing operation of the seeds, followed by a drying operation of the pressed seeds.

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13/20 [0051] The purpose of seed conditioning is to make the oil as accessible as possible to alcohol, without however changing its mechanical resistance. This prevents the formation of a mass and fine coal, respectively harmful to the implementation of a continuous process and to the final purification of the esters produced. In addition, the conditioned seeds must allow an easy passage of the reaction fluid (alcohol mixture - basic catalyst) according to a simple percolation phenomenon.

[0052] According to a variant of embodiment, fresh seeds are pressed under a mechanical press with smooth or fluted rolls.

[0053] The seeds thus pressed are dried, for example in a thermoregulated ventilated greenhouse or in a continuous banded or rotary hot air dryer. The drying duration and temperature are chosen to obtain a decrease in seed moisture to values less than or equal to 2% by weight. Preferably, drying is carried out quickly after pressing in less than an hour, preferably after 5 to 10 minutes, at a temperature sufficient to reduce the seed moisture content to a maximum of 2% by weight. [0054] The residual moisture of the seed is determined through thermogravimetry. The seed is previously crushed and then the obtained crush is dried at 105 ° C on a thermal scale until the weight stabilizes. The water content is expressed as a percentage of the raw material.

[0055] In a preferred embodiment, step 1) seed conditioning also includes a seed preheating operation, carried out before the pressing operation. This preheating operation gives the seed greater plasticity and, therefore, a more effective crushing when pressing (gain in terms of the contact surface, the percolation speed of the alcohol and, therefore, its extractive capacity). It occurs preferably at a temperature less than or equal to 100 ° C.

[0056] The implementation of the different process variants according to the invention is illustrated by the schematic representations of figures 1 to 4 in which,

1: represents the seed supply

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14/20

2: represents the supply of methanol (alcohol)

3: represents the part rich in heptanaldehyde

4: represents the part rich in methyl ester of ω unsaturated C11 / C13 acid

5: represents the part rich in non-hydroxylated methyl esters

6: represents the methyl ester-rich part of the unconverted hydroxylated fatty acid

7: represents glycerol

R1: represents the seed milling unit or reactive seed milling unit

R2: represents the transesterification unit of vegetable oil

R3: represents the thermal cracking unit of the ester mixture

R4: represents the optional unit for the esterification of the part rich in methyl esters of unconverted hydroxylated fatty acids

S1: represents the unit of separation of heptanaldehyde from other R3 products

S2: represents the unit of separation of the methyl ester of ω-unsaturated C11 / C13 acid from the other unbroken methyl esters

S3: represents the unit of separation of hydroxylated methyl esters from the other esters.

[0057] Figure 1 illustrates the process according to which

- the oil from the seed introduced in (1) is extracted in R1 by means of classical grinding in the presence or not of a solvent not shown,

- transesterification of triglycerides in the methanol medium introduced in (2) is carried out in R2, at the exit of R2 the glycerol in the medium is separated in (7),

- the separation of esters of non-hydroxylated acids transferred in S3 is carried out in S3, with the hydroxyl esters being directed to R3,

- in R3 the fraction of hydroxylated esters is subjected to pyrolysis in the presence of water vapor (not shown),

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15/20

- the R3 effluent is destined for S1 where heptanaldehyde is separated into (3), after

- the mixture of the remaining esters is destined for S2, where the ester of the C11 / C13 ω-unsaturated acid is separated into (4) from the other unbroken methyl esters which are recycled to R3,

- the recycled fraction is directed to R4 where an esterification in methanol medium (not shown) is carried out to eliminate the acids eventually formed during pyrolysis, a fraction of unbroken methyl esters maybe transferred in (6) is totally recycled to R3.

[0058] Figure 2 illustrates a process according to which reactive grinding of seeds captured in (1) in methanol introduced in (2) takes place within R1; the R2 reactor is released. The glycerol is extracted from R1 in (7) and the process is strictly identical to the one just described.

[0059] Figure 3 illustrates a process whose initial phases are identical to those of figure 1 until the outlet of R2, according to which the entire mixture of esters of R2 is directed to the cracking reactor R3. The effluent leaving R3 is subjected to a series of separation in S1 for heptanaldehyde in (3), then in S2 for the C11 / C13 ω-unsaturated acid ester in (4) and finally in S3 for the esters of non-hydroxylated acids in (5). The output of the unconverted and non-recycled hydroxy esters to R3 is carried out in (6). The recycling of hydroxy esters not converted to R3 goes through an esterification in R4.

[0060] Figure 4 illustrates a process according to which reactive grinding of seeds captured in (1) in methanol introduced in (2) takes place within R1; the R2 reactor is released. The follow-up of the process is strictly identical to what has just been described for figure 3.

[0061] For the manufacture of the biodiesel fuels of the invention, it will be advantageous before final mixing to subject the parts leaving in (4) and (5) to an esterification to eliminate any trace of acid form.

[0062] The biodiesel of the invention will be illustrated by the examples below

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16/20 conducted from a single source of hydroxy acids, castor oil (and more generally castor seeds).

[0063] Example 1 (comparative) [0064] The mixture "biodiesel" A is obtained by simple transesterification of crude castor oil without cracking or recycling. It leads to the following mixture of esters expressed in% by weight:

C11: 1: 0

C16: 0: 1,3

C18: 0: 1.5

C18: 1: 4

C18: 1 OH: 86

C18: 2: 5 [0065] Conventionally "C10" indicates the number of carbon atoms (10 in this case) ": 1" the number of unsaturations (one in this circumstance) and "OH" the presence of a hydroxyl function.

[0066] This mixture has a cetane number, measurable according to EN 14214: 2003 (or ASTM D6751-07a), very weak in relation to the specification (> 47 or 51). Its viscosity according to the same standards, very high 13.8 mm ² / s at 40 ° C (2-6), resistance to cold (melting point) very high 6.7 ° C (<-20 ° c ).

[0067] Example 2 [0068] The "biodiesel" mixture B will be manufactured from mixture A followed by cracking at a conversion rate of 70%, then a separation of the formed heptanaldehyde and, finally, the complementary esterification of mixture of esters obtained.

[0069] It will lead to the following mixture of esters expressed in% by weight:

C11: 1: 49.8

C16: 0: 1,7

C18: 0: 2.0

C18: 1: 5.3

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C18: 1 OH: 34.4

C18: 2: 6,7 [0070] This biodiesel will have a cetane number of 50.3, but within the specification, at the lower limit, an estimated viscosity of 7.5, slightly strong, slightly above specification, a resistance to cold quite good 17.9 ° C, but slightly above winter specification. This mixture would be a correct biodiesel fuel and can be used alone, without the need for mixing.

[0071] Example 3 [0072] A mixture of biodiesel C will be manufactured from mixture A followed by cracking, at the end of which the mixture of aldehyde C7 will be extracted, then the C11 ω-unsaturated ester will be separated and finally the part rich in residual ricinoleic ester will be separated to be recycled in the cracking of other C18 / C16 esters. At the end of these operations, the C11 ω-unsaturated ester and the other C18 / C16 esters will be mixed, but not the ricinoleic ester.

[0073] It will lead to the following mixture of esters expressed in% by weight:

C11: 1: 57.1

C16: 0: 4.7

C18: 0: 5.5

C18: 1: 14,6

C18: 1 OH: 0

C18: 2: 18,2 [0074] This biodiesel will be exceptionally good with a cetane number of 56, a viscosity close to 3.6, in the lower range, very good resistance to cold below -20 ° C. This type of mixture could almost be used without the need for an external supplement.

[0075] Example 4 [0076] A biodiesel D will be manufactured from Mixture A followed by cracking at the end of which the mixture of heptanaldehyde and methyl ester of undecylenic acid will be extracted after which a partial extraction of the part will be carried out

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18/20 rich in ricinoleate for recycling in cracking. The biodiesel mixture D will consist of the 10-undecylenic ester and the mixture of C16 / C18 esters plus the part of the non-recycled ricinoleate fraction.

[0077] It will lead to the following mixture of esters expressed in% by weight:

C11: 1: 50

C16: 0: 4

C18: 0: 5

C18: 1: 12

C18: 1 OH: 14

C18: 2: 15 [0078] The cetane index of this biodiesel will be good, above 50, and will show good resistance to cold close to -20 ° C.

[0079] Example 5 [0080] This example illustrates a “theoretical” biodiesel E consisting of the liquid effluent leaving the cracking reactor after simple separation of the heptanaldehyde. Its theoretical composition (the exact cracking rate is not known) should be as follows.

C11: 1: 42,9

C16: 0: 3,6

C18: 0: 4.1

C18: 1: 10,9

C18: 1 OH: 24.9

C18: 2: 13,7 [0081] Their performance will be lower than that of biodiesel C and D.

[0082] The set of processes implemented led to a “by-product”, heptanaldehyde. However, the producer will be able to value this heptanaldehyde, which is an interesting product for the industry in the form of heptanal, acetal, acid, alcohol, nitrile ...

[0083] The diesel fuel compositions of the invention are illustrated by the following examples.

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19/20 [0084] Example 6 Preparation of a mixture between a diesel and the 10-undecenoic acid methyl ester.

[0085] The ester of 10-undecenoic acid is prepared by thermally cracking a methyl ester of castor oil. The methyl ester of 10undecenoic acid is isolated by distillation. Such a compound is commercially available and produced on request.

[0086] The 10-undecenoic acid methyl ester obtained is then mixed with a diesel fuel base representative of the Euro 2000 formulations: density in the range of 0.830 to 15 ° C, sulfur content in the range of 290 ppm, cetane index of

51, distillation range 170-360 ° C. The 10undecenoic acid / base fuel methyl ester ratio is 10% by weight. The cetane number of the mixture is then measured according to the ISO 5165 standard. This is slightly higher than 51, which allows to infer that the cetane number of the acetal in the mixture is of the order of

52.

[0087] Example 7 Comparative tests of the mixture with the base diesel fuel.

[0088] Tests are carried out with the objective of evaluating the particle emission performance of diesel fuel compositions containing 10% by weight of the 10-undecenoic acid methyl ester compared to those obtained with the reference diesel fuel.

[0089] The tests were carried out in a diesel vehicle equipped with a direct injection engine. These tests were carried out in the cycle described in the European Directive 70/220 / EC, modified by the directive 98/69 / EC (cycle called MVEG-11s EURO 2000). This cycle consists of an urban phase (EUDC cycle 4,052 km long) and an extra-urban phase (ECE cycle 6,955 km long). The test results, expressed in milligrams of particles per kilometer, are as follows:

[0090] Diesel fuel alone: ECE cycle 65 mg / km, EUDC cycle 52.5 mg / km, MVEG cycle 57 mg / km [0091] Diesel fuel 90% + 10% acid methyl ester 10Petition 870180017594, from 05 / 03/2018, p. 24/29

20/20 undecenoic: ECE cycle 47 mg / km, EUDC cycle 55 mg / km, MVEG cycle 47 mg / km. [0092] The reduction of particulate emissions with the fuel according to the invention is in the order of 10%.

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1/3

Claims (9)

1. Biodiesel fuel, characterized by the fact that it comprises a mixture of fatty acid esters, said mixture containing a compound of natural non-fossil origin of formula ROOC- (CH2) n-CH2-R1 where R is either CH3 or C ₂ H ₅ , n is 7 or 9 and R ₁ is either C ₂ H ₅ or CH = CH ₂ , where the weight content of said non-fossil compound in the mixture is between 20 and 70%. 2. Fuel according to claim 1, characterized by the fact that the content of this compound is between 30 and 60%. Fuel according to either of claims 1 or 2, characterized in that this compound corresponds to the formula CH ₃ OOC- (CH ₂ ) ₈ -R ₁ where R1 is either C2H5 or CH = CH2. Fuel according to either of claims 1 or 2, characterized in that this compound corresponds to the formula CH ₃ OOC- (CH ₂ ) ₁₀ -R ₁ where R1 is either C2H5 or CH = CH2. 5. Process for manufacturing a diesel fuel according to claims 1,2, 3 or 4, characterized by the fact that castor seed oil and / or Lesquerella oil is used as a raw material that is subjected to a transesterification reaction of triglycerides with a weak alcohol, preferably methanol, then, after separation of the glycerol formed, the non-hydroxylated fatty esters separate to form a hydroxyester-enriched fraction, then the hydroxyester fraction of the ricinoleic acid and / or enriched lesquerolic acid is broken down to form the acid ester of the formula ROOC- (CH2) n-CH2-R1, where R is either CH3 or C2H5, n is 7 or 9 and R1 is CH = CH2, without this cracking having an impact on the residual C18 unsaturated esters then, after separation of the formed heptanaldehyde, an effluent is produced comprising ω-unsaturated esters C11 and / or C13 and hydroxy esters of unprocessed ricinoleic and / or lesquerolic acids in the previous cracking which after mixing with the fatty esters Non-hydroxylates separated previously will form said biodiesel fuel. 6. Process according to claim 5, characterized in that, after the separation of the heptanaldehyde, the effluent is subjected to a separation of the Petition 870180017594, of 03/05/2018, p. 26/29 2/3 ω-unsaturated esters C11 and / or C13 and that the hydroxyester fraction of the ricinoleic and / or lesquerolic acids is totally or partially recycled in cracking after being subjected to an esterification with methanol. 7. Process according to claim 5, characterized by the fact that, after glycerol separation, all transesterification esters are subjected to cracking whose effluent is subjected to a series of successive separations, from heptanal to ω-unsaturated esters C11 and / or C13, finally followed by non-hydroxylated fatty esters, the residual hydroxyester fraction of unprocessed ricinoleic and / or lesquerolic acids being totally or partially recycled after cracking after being subjected, if necessary, to an esterification with methanol, the fuel biodiesel being constituted by the mixture of ω unsaturated esters C11 and / or C13, non-hydroxylated fatty esters and eventually the transferred part of hydroxy esters of ricinoleic and / or non-converted lesquerolic acids. 8. Process for manufacturing a diesel fuel according to claim 1, 2, 3 or 4, characterized by the fact that castor and / or Lesquerella seeds are used as raw material, which are conditioned with an acidity rate of less than 2 mg KOH / g without prior peeling, then put in contact with a weak anhydrous alcohol, preferably methanol and an alkaline catalyst under conditions of sufficient temperature and duration to allow simultaneous extraction and transesterification of the vegetable oil and leading to obtaining of a mixture comprising the fatty acid esters present in the seed, glycerol and a cake, then, after separation of the formed glycerol and cake, cracking of the resulting ester fraction, containing an important proportion of ricinoleic and / or lesquerolic ester to form the acid ester of the formula ROOC (CH ₂ ) _n -CH ₂ -R ₁ , where R is either CH ₃ or C ₂ H ₅ , n is 7 or 9 and R ₁ is CH = CH ₂ , without this cracking having impact on esters i unsaturated C18 present in the cargo and finally production, by separating the formed heptanaldehyde, from a mixture of esters constituting the biodiesel fuel. 9. Process according to claim 8, characterized by the fact that Petition 870180017594, of 03/05/2018, p. 27/29 3/3 that, after the heptanaldehyde separation, the mixture of esters is subjected to a separation of the ω-unsaturated esters C11 and / or C13, after the non-hydroxylated fatty esters and that the residual hydroxyester fraction of the ricinoleic and / or acids unconverted lesquerolic acid is totally or partially recycled in cracking after being subjected to an esterification with methanol, the biodiesel fuel being made up of a mixture of ω-unsaturated esters C11 and / or C13, non-hydroxylated fatty esters and possibly the hydroxy esters ricinoleic and / or leskerolic acids not converted. Petition 870180017594, of 03/05/2018, p. 28/29 1/2 FIGURE 1 FIGURE 2 2/2 FIGURE 3 FIGURE 4